Review Reports

Round 1

Reviewer 1 Report

In this paper convection heat transfer coefficients and pressure drops of four functionalized graphene nanoplatelet nanofluids based on the commercial coolant Havoline® XLC Pre-mixed 50/50 were experimentally determined to assess its thermal performance. The effect of nanoadditive loading, temperature and Reynolds number in convection heat transfer coefficients and pressure drops is discussed. A dimensionless analysis of the results is carried out and empirical correlations for the Nusselt number and Darcy friction factor are proposed. A maximum enhancement in the convection heat transfer coefficient of 7 % was found for the nanofluid with nanoadditive loading of 0.25 wt%. Contrarily, no enhancement was found for the nanofluids of higher functionalized graphene nanoplatelet mass fraction.

I think that results are interesting, the paper is well organized and well written.

So, I suggest taking into account the paper publication, with minor revisions.

The authors have to take into account the following comments:

in the abstract, at the line 22, please substitute “…drops is…” with “…drops are…”. On page 1, at the line 43, please substitute “Choi et al. …” with “Choi and Eastman …”. The same on page 2, at the line 46. On page 2, at the end of line 78, please delete the comma. On page 4, in the Table 1, there is a mistake in the parameters value. They are mm=10^-3 m, not 10³ Please correct it. On page 6, could the authors explain to me the equation (7). It is not clear for me. On page 7, in the equation (11) “p” has to be a pedix. On page 7, at the line 249, please substitute “c₆” with “c₅” On page 7, at the line 257, please substitute “…may not appropriate…” with “…may not be appropriate…”. On page 8, in figure 2, please delete the underlined style for the axes titles. In the nomenclature, please put the symbols in the alphabetic order. It is clearer for the reader. In the nomenclature the Si Unit of specific heat capacity is wrong. Please correct it. The authors could insert these references: Andreozzi, O. Manca, S. Nardini, D. Ricci, "Forced Convection Enhancement in Channels with Transversal Ribs and Nanofluids", Applied Thermal Engineering, Vol. 98, pp.1044–1053, 2016. Vallejo, J.P., Calviño, U., Freire, I., Fernández-Seara, J., Lugo, L., "Convective heat transfer in pipe flow for glycolated water-based carbon nanofluids. A thorough analysis", Journal of Molecular Liquids, 301, 1 March 2020, Article number 112370

Author Response

Manuscript ID: nanomaterials-693973
Type of manuscript: Article
Title: Cooling Performance of a Novel Circulatory Flow Concentric multi-Channels Heat Sink with nanofluids

Dear Eboni Yang,

The authors wish to thank all the Editors and reviewers for their unbiased and constructive suggestions, which led to this revised manuscript

All the comments are incorporated in the revised manuscript as summarized below:

Reviewer 1
1	in the abstract, at the line 22, please substitute “…drops is…” with “…drops are…”	We did not find the related text in abstract/manuscript. It seems comments received from Reviewer 1 are mismatched while uploading them from Reviewer 1 end.
2	On page 1, at the line 43, please substitute “Choi et al. …” with “Choi and Eastman …”.
3	The same on page 2, at the line 46. On page 2, at the end of line 78, please delete the comma.
4	On page 4, in the Table 1, there is a mistake in the parameters value. They are mm=10-3 m, not 103 Please correct it.
5	On page 6, could the authors explain to me the equation (7). It is not clear for me. On page 7, in the equation (11) “p” has to be a pedix.
6	On page 7, at the line 249, please substitute “c6” with “c5”
7	On page 7, at the line 257, please substitute “…may not appropriate…” with “…may not be appropriate…”.
8	On page 8, in figure 2, please delete the underlined style for the axes titles
9	In the nomenclature, please put the symbols in the alphabetic order. It is clearer for the reader. In the nomenclature the Si Unit of specific heat capacity is wrong.

Authors:

Ravindra Jilte, Mohammad Hosein Ahmadi, Ravinder Kumar, Vilas
Kalamkar, Dieu Tien Bui

Author Response File: Author Response.pdf

Reviewer 2 Report

Reviewers report: The manuscript “Cooling Performance of a Novel Circulatory Flow  Concentric multi-Channels Heat Sink with nanofluids “ by : Ravindra Jilte, Mohammad Ahmadi, Ravinder Kumar, Vilas Kalamkar and Dieu Tien Bui is devoted to study the influence of nanofluids on the

heat rejection rate. It was shown that nanoparticles insertion improves the heat dissipation.

It will be noted that in Fig.5 we can see no mass flow rate and no water outlet temperature.

After amendment the paper can be published.

Author Response

Manuscript ID: nanomaterials-693973
Type of manuscript: Article
Title: Cooling Performance of a Novel Circulatory Flow Concentric multi-Channels Heat Sink with nanofluids

Dear Eboni Yang,

The authors wish to thank all the Editors and reviewers for their unbiased and constructive suggestions, which led to this revised manuscript

All the comments are incorporated in the revised manuscript as summarized below:

Reviewer 2

Comment: It will be noted that in Fig.5 we can see no mass flow rate and no water outlet temperature. Response from Authors: Fig 5 is corrected in page 7, line 175

Authors:

Ravindra Jilte, Mohammad Hosein Ahmadi, Ravinder Kumar, Vilas
Kalamkar, Dieu Tien Bui

Reviewer 3 Report

The paper presents the experimental and numerical study of circulatory mini channel flow using nanofluids. The experimental and numerical results were presented well. Before get accepted the author should correct Fig. 10(b).   

Author Response

Manuscript ID: nanomaterials-693973
Type of manuscript: Article
Title: Cooling Performance of a Novel Circulatory Flow Concentric multi-Channels Heat Sink with nanofluids

Dear Eboni Yang,

The authors wish to thank all the Editors and reviewers for their unbiased and constructive suggestions, which led to this revised manuscript

All the comments are incorporated in the revised manuscript as summarized below:

Reviewer 3

Comment: Before get accepted the author should correct Fig. 10(b). Response from Authors: Fig 10 (b) is corrected in page 10, line 219

Authors:

Ravindra Jilte, Mohammad Hosein Ahmadi, Ravinder Kumar, Vilas
Kalamkar, Dieu Tien Bui